History of the sport.
Trials have been taking place for the last fifty years, starting in road going cars of the time. As the sport progressed, cars were adapted, and soon “specials” were the name of the day.
In the seventies, a VW based trials car was developed, which became very popular due to the copious availability of parts, and the agility of the rear engined car over the more cumbersome front engined specials.
However in the early eighties, a new hybrid front engine car was developed using a high revving Japanese Datsun 120 engine. This proved to be quite a competitor for the VW, and soon there was a number of front engine Datsun's on the circuit
Time passed, and a newer development of using a motorbike engine was experimented with. This gained additional power using some of the highly powerful 900-1300cc Japanese machines. Combined with lower gearing the Datsun's were soon seen as out manoeuvred, while the VW's (of which many are still competing) seemed destined for obsolescence.
Climate change I think, forced a gradual re-think of the courses over the ninetys and noughtys as our winters became less muddy, and the sections duly became tighter and more skillful to complete. This ironically saw the nimble VW based cars return to the podium, as when well driven these cars can once again be competitive, often taking the overall trophy.